Tourism is now taking up about 10% of the GDP of the entire world, and is predicted to become the largest industry in the 21st century from now on.
Under the circumstances, there have been growing needs for tourism not only in conventional tourist spots, but also in unexplored places and frontier spaces such as space and deep sea.
However, if many tourists rush in to crowd into secluded places, then they tend to suffer problems in that rare natural environments and precious ruins are likely to be destroyed. Sightseeing in frontier spaces such as cosmic space and deep sea is not only costly because the tourists have to go to actual sightseeing spots, but also excessively physically burdensome for the tourists owing to surrounding environments including zero gravity and high atmospheric pressure to which they are to be exposed, and risky in that the lives of the tourists may be put in jeopardy in the event that a vehicle (such as a spacecraft or a deep ocean research vehicle) for carrying the tourists to a sightseeing spot is broken.
One solution to the above problems would be to give users at distance places a pseudo-sightseeing experience by displaying the image of a sightseeing spot for the tourists. However, if the display range of a video image that is displayed is set by a person other than the users, then the displayed video image remains the same as those of videophone and live television broadcasts, but is far from the “sightseeing experience”. In order to give users a pseudo-sightseeing experience, it is necessary to provide a live video distribution system which allows users at distant places to set the display image of a video image by themselves and to observe, in real time, a target that the users want to observe.
Heretofore, there have been proposed live video distribution systems which allow a user at a distant place to set the display image of a video image by themselves, such as “remote monitoring camera” disclosed in Patent document 1 (hereinafter referred to as “Prior art 1”) and “monitor system using unmanned helicopter” disclosed in Patent document 2 (hereinafter referred to as “Prior art 2”).
However, since these conventional systems have a device for capturing a video image and a device for displaying a video image, which are provided as a pair, only one user at a time is capable of setting the display range of a video image. As a result, the conventional systems are unable to let a plurality of users simultaneously observe a separate target on the spot.
Of the conventional systems, the device for displaying a video image is of the type for displaying a video image on a screen (e.g., a CRT display, an FDP, a projector, or the like). The user stays still and sees a video image displayed on the screen while fixing its line of sight to the screen. Consequently, even though the user can move the display range of the video image, the motion of the display range of the video image, and the motion of the body of the user and the motion of the line of sight are not linked to each other at all. The user cannot enjoy the displayed video image in a realistic manner as if the user is observing the target on the spot themselves.
According to Prior art 1, in particular, a monitor camera 1 for capturing a video image is fixedly mounted on a camera platform 2. Inasmuch as the viewpoint cannot be moved though the line of sight along which the target is observed can be moved, images that are displayed on a video display 7 are limited to those of observation targets that are present around the camera platform 2. According to Prior art 2, an image signal is directly transmitted through a wireless link from an image transmitter 5 on an unmanned helicopter H to an image receiver 6 on the image display 7. Therefore, the system according to Prior art 2 is problematic in that the distance between the site where the observation target is present and the distant place where the user is present cannot be greater than the distance over which the wireless image signal can be transmitted.
The terms “image capturing range”, “vantage point”, “line of sight”, and “viewpoint (center of the image capturing range)” used in the present description and the scope of claims for patent are referred to in FIG. 4 of the accompanying drawings.